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Engineering Data Book III

Chapter 1
Video Gallery of Flow Phenomena
(This chapter was updated in 2007. Note: the new videos require use of an updated video player.)
Summary: Numerous videos have been assembled here for two-phase flows and heat transfer phenomena
(and still more will be added in the future) and are available here for the reader to view. Presently, only
two-phase videos areshown but videos of single-phase enhancement phenomena will be included in the
future.

1.1 INTRODUCTION TO THE VIDEO GALLERY
The motive behind the preparation of this video gallery is to make videos of single-phase and two-phase
flow and heat transfer phenomena available for general viewing. For thermal designers normally
performing computer calculations on heat exchangers, this is anopportunity for them to actually see what
some of the processes really look like, albeit in idealized test conditions. The idea is also to make this
chapter a forum to display interesting videos of such phenomena for others to see.
Note: Since the original video files are typically too large (5-40 Megabits) to view directly via the
internet, the videos shown have had to cut to short time sequences(typically 2 seconds or less) that are
looped to give the sensation of a continuous process and also processing of the images has been applied to
achieve smaller file sizes, but at a small lose of quality. Some patience may be required on behalf of the
reader to view these video files via the Internet.
To use this chapter: The chapter is organized by type of flow. Within each section, videosare listed by
the flow process they show; the reader needs only to click on the video of his choice on the list to see the
video and also obtain a brief description of the test setup and experimental conditions.

1.2 TWO-PHASE FLOW PATTERNS IN HORIZONTAL TUBES
Figure 1.1 depicts a two-phase flow pattern map for flow in a horizontal tube, illustrating the types of
two-phase flow patternstypical of these flows and the range of conditions where particular flow regimes
occur. Within a horizontal evaporator tube, Figure 1.2 depicts a composite diagram of the flow patterns
that may be encountered when going from a subcooled liquid to complete evaporation. Similarly, Figure
1.3 shows composite diagrams of flow patterns confronted in condensation at high and low flow rates.
The videosin this section, listed below, show numerous examples of these flows.

Video Gallery of Flow and Heat Transfer Phenomena

1-1

Engineering Data Book III

Figure 1.1. Flow pattern map for R-22 at a saturation temperature of 5°C
(41°F) showing transition boundaries between two-phase flow regimes [where
G is the mass velocity of the liquid + vapor inside the cross-section of the tube
ofinternal diameter d = 13.82 mm (0.544 in.)].

Figure 1.2. Illustration of two-phase flow patterns occurring in horizontal
evaporator tube.

Video Gallery of Flow and Heat Transfer Phenomena

1-2

Engineering Data Book III

Figure 1.3. Illustration of two-phase flow patterns occurring in horizontal condenser tubes.
List of videos: (click on the one you wish to see)
Video 1.2.1: Bubbleflow. The video displays flow of isolated bubbles inside a horizontal sightglass of
14.0 mm (0.551 in.) internal diameter. This flow is at a moderate mass velocity at a very low vapor
quality and the bubble is essentially the initial step towards arriving at a plug flow. The fluid is ammonia
at 5°C (41°F). The video was taken by Dr. O. Zürcher in collaboration with Profs. J.R. Thome and D.Favrat at the Swiss Federal Institute of Technology Lausanne (EPFL). For a description of the test
facility, refer to: Zürcher, Favrat and Thome (2002).
Video 1.2.2: Stratified-wavy flow. The video displays a stratified-wavy flow (liquid in bottom and vapor
in top of tube) inside a horizontal sightglass of 14.0 mm (0.551 in.) internal diameter. The fluid is
ammonia at 5°C (41°F), a vapor quality...
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